Rice Influence on Grain Yield of Maize in Maize/Rice Mixture in the Northern Guinea Savanna Zone of Ghana

摘要

Intercropping maize (Zea mays) and rice (Oryza sativa L.) may ensure efficient and effective use of available resources, but little is known about its effect on the output of the staple crops. A field experiment was conducted to determine the effect of intercropping of maize in maize/rice mixture in northern Ghana in 2007 and 2008 using randomized complete block design with five treatments and four replications. Treatments were sole rice drilled (SRD), sole rice broadcast (SRB), sole maize (SM), rice drilled in maize/rice intercrop (MRD), and rice broadcast in maize/rice intercrop (MRB). Fertilizer was applied at planting at the rate of 60-30-30 kg/ha as N, P₂O₅, and K₂O. Additional 30 kg N/ha as ammonium sulfate was applied five weeks after planting. Grain yields from both monocrops were significantly higher than those from the intercrops. The trend was similar for straw weight and 100 seed weight. In 2007, maize yield losses caused by the inclusion of rice in the systems were 21% for MRD and 46% for MRB. In 2008, the reduction in maize yield was 27% for MRD and 43% MRB, suggesting that maize yield reduction in maize/rice mixture was higher when rice was broadcast than when it was drilled. The land equivalent ratio was more than one in both years, indicating yield advantage from intercropping maize and rice over growing the two crops in pure stands. We recommend that to maintain high maize yields in maize/rice intercropping system, it is better to drill than to broadcast the rice.